Volatile Organic Compound from TSU1: Impact on Plant Pathogenic Fungi.

Soil microorganisms are well studied for their beneficial effects on plant growth and their impact on biocontrol agents. The production of volatile antifungal compounds emitted from soil fungi is considered to be an effective ability that can be applied in biofumigants in the control of plant diseases. A soil fungus, TSU1, was isolated from flamingo flower cultivated soil and identified on the basis of the morphology and molecular analysis of the internal transcribed spacer (ITS), , and genes. To test TSU1-produced volatile organic compounds (VOCs) with antifungal activity, the sealed plate method was used. The VOCs of TSU1 inhibited the mycelial growth of fungal pathogens that were recently reported as emerging diseases in Thailand, namely, , , , , and with a percentage inhibition range of 38.88-68.33%. Solid-phase microextraction (SPME) was applied to trap VOCs from TSU1 and tentatively identify them through gas chromatography-mass spectrometry (GC/MS). A total of 17 compounds were detected in the VOCs of TSU1, and the dominant compounds were identified as fluoro(trinitro)methane (18.192% peak area) and 2-phenylethanol (9.803% peak area). Interestingly, the commercial 2-phenyethanol showed antifungal activity against fungal pathogens that were similar to the VOCs of TSU1 by bioassay. On the basis of our study's results, TSU1 isolated from soil displayed antifungal abilities via the production of VOCs responsible for restricting pathogen growth.